1 / 17

Early-Age Microcrack Detection in High-Performance Cementitious Materials

This study explores microcrack formation in cementitious materials and proposes detection methods using Gallium intrusion and crack examinations. By investigating autogenous shrinkage and crack development, the research aims to improve crack prevention strategies in high-performance concrete.

pbeller
Download Presentation

Early-Age Microcrack Detection in High-Performance Cementitious Materials

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Microcrack Detectionin High-Performance Cementitious Materials Pietro Lura, Ye Guang, Kyoji Tanaka, and Ole Mejlhede Jensen

  2. Early-age cracking Tokyo Institute of Technology, Yokohama, Japan

  3. Microcracking (Bisschop & van Mier 2002)

  4. Chemical shrinkage Autogenous shrinkage Definitions (Jensen & Hansen 2001) solid water air

  5. Autogenous shrinkage in HPC • Less water • More cement • Silica fume

  6. Internal microcracking • Does autogenous shrinkage lead to internal cracks? • How to detect them?

  7. Superabsorbent polymers (SAP)

  8. Autogenous relative humidity Paste C (w/c 0.30 + 20% SF +0.6% SAP) Paste A (w/c 0.35) Paste B (w/c 0.30 + 20% SF)

  9. Autogenous strain Paste C (w/c 0.30 + 20% SF +0.6% SAP) Paste A (w/c 0.35) Paste B (w/c 0.30 + 20% SF)

  10. Samples for crack detection - 3 cement pastes • 1.5, 3, and 6-mm rods • sealed at 32C

  11. 10 1.2 µm ] 1 m µ [ r e t e m a i d e 0.1 r o P 0.01 1.6 MPa 0.1 1 10 100 Intrusion pressure [MPa] Properties of Gallium - melting point 29.8 C • does not wet cement paste • nontoxic

  12. Gallium intrusion

  13. Sample preparation • epoxy resin • grinding • polishing • crack examination: - optical microscope - BSE - EPMA

  14. Crack detection (1)

  15. Crack detection (2)

  16. Conclusions • Cracks before intrusion can be distinguished • High shrinkage, big rod  Cracks

  17. Further research • EPMA • Acoustic Emission • FE calculations

More Related